The aim of this study was to quantify the amount of phenolic compounds and flavonoids in extracts from Thymus vulgaris and Origanum vulgare L. and to evaluate the antioxidant activity of these extracts. Extracts were obtained by employing three different techniques: low pressure solvent extraction, Soxhlet, and ultrasound methods. The effects of phenolic and flavonoid concentrations on the percentage of inhibition of free radical activity were also analyzed. The highest amounts of phenolic compounds were obtained with Soxhlet and Low Pressure Solvent Extraction (LPSE) for thyme and oregano respectively. The highest flavonoid levels were obtained by the Soxhlet extracts for both species. All extracts showed strong antioxidant activities. Manuscript profile